Beware of Sunburn Boosters

> It was a day outdoors like many others and you had slathered on thesunscreen only to end up with a wicked sunburn. What went wrong? The answer maylurk in your medicine cabinet. Certain drugs and other substances can increasethe skin's sensitivity to ultraviolet light and cause the skin to burn in lesstime or at a lower intensity of sunlight than it would normally.

Sunburn is a serious matter. Exposure to the sun's ultraviolet (UV) rays isa known risk factor in skin cancer skin cancer . The American Cancer Society estimatesthere will be 59,940 new cases of melanoma melanoma , the most serious form of skin cancer, in2007. The death rate has increased 50% since 1973. WebMD talked with twoexperts about medications that heighten your risk for sunburn and how to staysafe in the sun.

The Leading Culprits

Diuretics.Hydrochlorothiazide (HCTZ) is a commonly used diuretic("water pill") used to treat high bloodpressure high bloodpressure . Combination drugs, which contain HCTZ, include Maxide,Dyazide, Hyzaar, and Zestoretic.

Antibiotics. Tetracycline drugs, which include Sumycin,Tetracyn, and Vibramycin, are used to treat bacterial infections. Quinolonedrugs like Cipro, which gained attention during the anthrax scare, and sulfadrugs, such as Bactrim, also heighten sun sensitivity. Cipro and Bactrim areantibiotics often used for urinary tract infections.

Balsam of Peru. This herbal ingredient is often used inperfumed products and aftershave lotions.

Shedding Light on the Subject

Heightened sensitivity to sun, or a phototoxic reaction, occurs whenultraviolet rays interact with certain chemicals in medications. Even after youhave stopped taking a drug, its effects may linger. "Depending on the typeof drug and how long you've been taking it, it can remain in your system fromone to five days," says Bill Bailey, RPh, director of specialized carecenters for Medicine Shoppe in St. Louis. "To be on the safe side, alwaysask the pharmacist about the effects of your medications on sun exposure.They'll go online and get current, accurate information," he says.

You don't even have to go out in the sun to experience the complications ofmedications. You could easily get sunburned in a tanning salon, saysdermatologist Craig Eichler, MD. "There have been some bad cases. Tanningbooths primarily emit UVA rays, and that's what medications mainly interactwith."

And here's another little-known fact about UV rays: They penetrate water."Swimmers don't realize they can get sunburned under water," saysEichler. Water also reflects UV rays, which can add to your exposure.

SPF, UVA, UVB, and Some Good News

There's a debate over whether sunscreens with high SPF ratings provide anymore protection than one rated SPF 15. "I recommend SPF 15. The strongersunscreens often give people a false sense of security," says Bailey.

Eichler says SPF 15 blocks 92% of UVB rays, while SPF 30 blocks 97%."SPF 15 is fine for going toand from the store, but use SPF 30 for longersun exposure or if you're taking medications."

Whether you use sunscreens with SPF 15 or 45 ratings, you're buyingprotection from UVB rays, says Eichler, who is with The Cleveland ClinicFlorida in Naples. For protection against UVA rays, a product must contain oneof the following active ingredients: zinc oxide, titanium dioxide, oravobenzone (Parsol 1789). "A problem is that these ingredients aren'tstable for a very long time."

That's one reason he's glad to see that the FDA has just approved ecamsule,a broad-spectrum sunscreen that has been marketed since 1993 as Mexoryl SX inEurope and Canada. It protects against both UVA and UVB rays and has an SPF 15rating. It is expected to become available in the U.S. over the countersometime in the fall as Anthelios SX.

Protecting Yourself

Eichler recommends reapplying sunscreen every couple of hours and makingsure to use enough. "Most people use at best half of what they need. If youput it on too thin, it doesn't give you protection." The American CancerSociety says the average adult should use about a palm-full of sunscreen tocover the arms, legs, neck, and face.

The key to effective sunscreen use is to reapply it often. Bailey advisesapplying it one-half hour before you go into the sun, and every half houryou're exposed. "Sunscreen wears off when you're sweating or in the water.Remember to cover your hands and feet with sunscreen, too."

Both experts tell WebMD you can't rely on sunscreen alone. Wear a hat, coverup, and avoid reflected rays from sand, concrete, and metal, which can reachyou even if you've blocked the sun with an umbrella. Also stay out of the sunduring the peak hours of 10 a.m. to 3 p.m.